In the process at looking over the german replacements rates, i stumbled across this:

From the manual

21.1.10.1. Manpower Production Each nation has a separate manpower pool, with a small percentage of the Czech and Polish manpower going to the German pool.

Looking at the polish manpower production after running one turn, as it is as easy to test ill not provide a saved turn, u see a production of 3237 build by 434 capacity. Well the math as i understand it for german is 1630 factories * 9 for '41 *0.85 in theater multiplier = 12469,5. The german production is in fact i assume due to rounding off 12385, not that u can see that in the pic. The math in game seems for polish to be the same then 434*9*0.85 =3320,1. Rounding offs presumably taking it too 3237.

The wording above and the /8% modifier at the polish/czech as said seems to suggestion only a fraction of the polish/czech manpower should be availble to the german pool. Does that in effect mean that of the 3237 a small number transferes to the german pool and this is "hidden" for the players? Or that there from the polish pool are 3237 manpower availble for the germans to draw on per turn. If the latter is true it seems odd as the combined polish/czech manpower per turn attritubes 35% of the german manpower. Hardly seems like a fraction and the replacement drawn from Poland/Czech is then same proportion of population as the german population as the math is the same. Again if the latter is true i assume a bug has crept in.

The wording above and the /8% modifier at the polish/czech as said seems to suggestion only a fraction of the polish/czech manpower should be availble to the german pool. Does that in effect mean that of the 3237 a small number transferes to the german pool and this is "hidden" for the players?

8% transfer happens during the logistic phase. Action is labeled as "Convert Non-German Production". After conversion pools are cleared.